Actin-Dependent Alterations of Dendritic Spine Morphology in Shankopathies

Figure 4

Small GTPases act like a molecular switch. Small GTPases are active when they are GTP bound and inactive when they are GDP bound. The switch between active and inactive state is mediated by modulators, mainly GAPs (GTPase activating proteins) and GEFs (guanosine exchange factors). GAP hydrolyzes the bound GTP to GDP and GEF exchanges the GDP with GTP. Besides GAPs and GEFs, there is another kind of modulators—GDI (GDP dissociation inhibitors).